Maternal transmission risk and antibody levels against hepatitis B virus e antigen in pregnant women.

BACKGROUND: The generation of antibodies (anti-HBe) against hepatitis B virus (HBV) e antigen (HBeAg) often coincides with clinical remission in chronic HBV patients. We aimed to examine the effect of maternal anti-HBe in protection against HBV mother-to-child transmission (MTCT). METHODS: A total of 140 chronic HBV-infected pregnant women participated in this study. Before delivery, maternal HBV serological markers and HBV viral load were determined and anti-HBe titers were semi-quantified. Neonatal hepatitis B surface antigen (HBsAg) and HBV-DNA status were determined from cord blood. The children were followed to age 1-3 years. RESULTS: The HBV-DNA positive rate in cord blood was 75.61% (31/41) in those who were born to mothers with serum HBV-DNA >10(6) IU/ml, which was significantly higher than in those who were born to mothers with HBV-DNA <10(6) IU/ml (3/99, 3.03%; p<0.0001). However, 10 newborns from mothers with serum HBV-DNA >10(6) IU/ml had no detectable HBV-DNA in cord blood; anti-HBe was positive with a median titer of 10 (interquartile range 10-55). A total of 84 children who received hepatitis B immune globulin (HBIG) within 12h after birth and who completed three doses of recombinant HBV vaccination were followed to age 1-3 years (up to May 2014). All 56 children who were born to mothers with serum HBV-DNA levels <10(6) IU/ml were HBsAg-negative. Five of the 22 children born to anti-HBe-negative mothers with serum HBV-DNA >10(6) IU/ml acquired an HBsAg-positive status. However, none of the six children who were born to anti-HBe-positive/weak-positive mothers with serum HBV-DNA >10(6) IU/ml acquired an HBsAg-positive status. CONCLUSIONS: The presence of maternal anti-HBe is protective against HBV MTCT, independent of the maternal serum HBV viral load.